IVF due date calculator
Weeks pregnant and days until your due date after an embryo transfer, fresh or frozen.
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How it's calculated
Pregnancy is dated from a theoretical last period two weeks before conception, so a 40-week pregnancy is really 38 weeks (266 days) from fertilization. With IVF, fertilization happened on the day of egg retrieval, and the embryo age at transfer tells you how many of those days had already passed. A day-5 embryo is 5 days past fertilization, so on transfer day you count as 2 weeks and 5 days pregnant, and the due date is 261 days after the transfer. A day-3 transfer adds 263 days and a day-6 transfer adds 260. Fresh and frozen transfers are dated the same way, since freezing pauses the embryo’s development. Weeks pregnant counts from that start point to today. If your clinic gives you different dates, theirs take priority.
How is an IVF due date calculated?
Add 266 days to the transfer date, then subtract the embryo age. For a day-5 embryo that is 261 days after transfer, for a day-3 embryo 263 days, and for a day-6 embryo 260 days.
Is the due date different for a frozen embryo transfer?
No. Freezing pauses the embryo’s development, so a frozen day-5 embryo is dated exactly like a fresh one: 261 days from the transfer.
How many weeks pregnant am I after a day-5 transfer?
On transfer day you count as 2 weeks 5 days pregnant. Nine days later, around the time many clinics do the first blood test, you are 4 weeks 0 days.
Can I use this before my transfer?
The weeks-pregnant results need the actual transfer date, so enter it once the transfer has happened. For planning, the last result shows how many days after transfer the due date falls: 261 for a day-5 embryo.
What about a fresh cycle or an IUI?
For a fresh cycle, you can also count from egg retrieval as day 0: the due date is 266 days after retrieval. An IUI is dated like a natural conception, so use the pregnancy due date calculator with the date 14 days before the insemination as your last period.
Are IVF due dates more accurate?
The start date is more precise, because the embryo age is known exactly rather than estimated from a period. The birth date is no more predictable, though: most babies still arrive within about two weeks either side of the due date.
Is the due date different for twins?
It is calculated the same way. Twin pregnancies often deliver before 40 weeks, so your doctor will plan around an earlier delivery window.
Results are estimates for informational purposes only and are not financial, medical or legal advice.